检索结果-南通市图书馆

Journal.of Material. Science & Technol.gy 2021年第18期77卷 38-46页

作者： Y.chew Z.G.Zhu F.Weng S.B.Gao F.l.ng B.Y l.e G.J.Bi Singapore Institute of Manufacturing Technol.gy 73 Nanyang Drive637662Singapore School.of Mechanical.Aerospace Engineering Nanyang Technological University50 N any ang Avenue639798Singapore

l.ser aided additive manufacturing(l.AM)was used to fabricate bul. Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial.mul.icomponent al.oy using pre-al.oyed *** room temperature yiel. strength(σ_y),ul.imate tensil. strength(σ_(UTS))and el.ngation(ε_(UTS))were 645 MPa,917 MPa and 27.0%*** asbuil. sampl. consisted of equiaxed and dendritic cel.ul.r structures formed by el.mental.*** cel.ul.r structures together with oxide particl. incl.sions were deemed to strengthen the *** other contributing components incl.de disl.cation strengthening,friction stress and grain boundary *** highε_(UTS)was attributed to disl.cation motion and activation of both twinning and transformation-induced pl.sticity(TWIP and TRIP).Tensil. tests performed at-40℃and-130℃demonstrated superior tensil. strength of 1041 MPa and 1267 MPa ***,al.ost no twinning was observed in the fractured sampl. tested at-40℃and-130℃.Instead,higher fraction of strain-induced hexagonal.cl.se-packed(HCP)εphase transformation of 21.2%were observed for fractured sampl. tested at-40℃,compared with 6.3%in fractured room temperature sampl..

关键词： Mul.icomponent al.oys l.ser aided additive manufacturing Additive manufacturing Microstructure Mechanical.property

Possibl. Rel.vance of the Al.ende Meteorite Conditions in Prebiotic chemistry: An Insight into the chondrul.s and Organic Compounds

在线全文

学校读者我要写书评

暂无评论

Advances in Biol.gical.chemistry 2023年第3期13卷 82-99页

作者： Al.jandro Heredia Barbero Héctor G. Vázquez l.pez Adriana l. Mel.ndez l.pez Jorge A. Cruz Castañeda Daniel.l.na l.viada Karina E. Cervantes de l. Cruz Victor Meza l.guna Vl.dimir A. Basiuk Ivonne Rosal.s chávez Al.cia Negrón Mendoza Sergio Ramos Bernal l.boratorio de Evol.ción Química Departamento de Química de Radiaciones y Radioquímica Instituto de Ciencias Nucleares Universidad Nacional Autónoma de México Ciudad Universitaria Ciudad de México México Programa de Posgrado en Ciencias Químicas Universidad Nacional Autónoma de México Ciudad Universitaria Ciudad de México México Departamento de Física Facultad de Ciencias Carrera de Ciencias de la Tierra Universidad Nacional Autónoma de México Ciudad Universitaria Ciudad de México México Departamento de Física de Pl.smas e Interacción de Radiación con Materia Instituto de Ciencias Nucleares Ciudad Universitaria Ciudad de México México Departamento de Física y Química Teórica Facultad de Química Universidad Nacional Autónoma de México Ciudad Universitaria Ciudad de México México

The study of the mineral.and organic content of the Al.ende meteorite is important for our understanding of the mol.cul.r evol.tion of the universe as wel. as the ancient Earth. Previous studies have characterized the magnetic mineral. present in ordinary and carbonaceous chondrites, providing information on the evol.tion of magnetic fiel.s. The interaction of organic compounds with magnetic mineral. is a possibl. source of chemical.diversity, which is crucial.for mol.cul.r evol.tion. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their rel.vance to the origins of chiral.ty in l.ving organisms. This study presents the characterization of organic and mineral.compounds in the Al.ende meteorite. The structural.and physicochemical.characterization of the Al.ende meteorite was accompl.shed through l.ght microscopy, powder X-ray diffraction with compl.mentary Rietvel. refinement, Raman and infrared spectroscopy, mass spectrometry, scanning el.ctron microscopy, and atomic force microscopy using magnetic signal.methods to determine the compl.x structure and the interaction of organic compounds with magnetic Ni-Fe mineral.. The presence of l.esegang-l.ke patterns of chondrul.s in fragments of the Al.ende structure may al.o be rel.vant to understanding how the meteorite was formed. Other observations incl.de the presence of magnetic material. and nanorod-l.ke sol.ds with rel.tivel. simil.r sizes as wel. as the heterogeneous distribution of carbon in chondrul.s. Signal. observed in the Raman and infrared spectra resembl. organic compounds such as carbon nanotubes and peptide-l.ke mol.cul.s that have been previousl. reported in other meteorites, making the Mexican Al.ende meteorite a feasibl. sampl. for the study of the earl. Earth and exopl.netary bodies.

关键词： Al.ende Meteorite Carbonaceous chondrite l.ght Microscopy X-Ray Diffraction with the Rietvel. Method Raman Spectroscopy Attenuated Total.Refl.ctance Infrared Spectroscopy Mass Spectrometry Scanning El.ctron Mi-croscopy Energy Dispersive X-Ray Spectroscopy Magnetic Force Microscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

香云纱真丝织物抗紫外线性能研究进展

丝绸 2024年第7期61卷 64-73页

作者：陈佳桦邹世杰吴炜郑晶晶吕健元浙江理工大学服装学院杭州310018 浙江理工大学先进纺织材料与制备技术教育部重点实验室杭州310018 浙江开源文化发展有限公司浙江湖州313200

香云纱作为国家级非物质文化遗产,是世界纺织品中唯一用纯植物染料染色的丝绸面料,具有天然环保、挺括顺滑、抗菌除臭、防晒防水等优势,被誉为“软黄金”。现阶段由于臭氧层的严重破坏,对人类健康及其他方面产生重要威胁,织物抗紫外线... 详细信息

香云纱作为国家级非物质文化遗产,是世界纺织品中唯一用纯植物染料染色的丝绸面料,具有天然环保、挺括顺滑、抗菌除臭、防晒防水等优势,被誉为“软黄金”。现阶段由于臭氧层的严重破坏,对人类健康及其他方面产生重要威胁,织物抗紫外线性能研究逐渐成为纺织品行业的重要方向。相比于普通真丝织物,香云纱由于特殊染整工艺,具有优异的紫外线防护性能。但该染整过程较为传统,实际生产具有较大限制,行业产业化率低。基于此文章综述了香云纱特殊染整工艺及其抗紫外线性能、其他真丝织物抗紫外线研究等内容,总结了香云纱抗紫外线染整过程存在的问题与改进方向,并对其发展趋势进行了展望,以指导实际生产应用,为未来香云纱产品设计创新及性能改善提供借鉴,提升产品服用性能,推动行业发展。

关键词：香云纱国家级非物质文化遗产真丝织物抗紫外线改性处理绿色低碳多功能性丝绸

同方期刊数据库博看期刊

农药施用对兴凯湖水中农药残留的影响及其风险评价

在线全文

学校读者我要写书评

暂无评论

环境科学 2024年第5期45卷 2678-2685页

作者：王蔚青徐雄刘权震林利华吕婧王东红中国科学院生态环境研究中心工业废水无害化与资源化国家工程研究中心北京100085 中国科学院大学北京100049

主要研究了中国东北兴凯湖周围水稻种植区域农药残留以及对湖水水质的影响.分别于水稻抽穗期和水稻成熟期在兴凯湖地区对稻田、排干和大小兴凯湖地表水进行采集并对27种农药及其降解产物进行分析.结果表明,在水稻抽穗期所分析的27种农... 详细信息

主要研究了中国东北兴凯湖周围水稻种植区域农药残留以及对湖水水质的影响.分别于水稻抽穗期和水稻成熟期在兴凯湖地区对稻田、排干和大小兴凯湖地表水进行采集并对27种农药及其降解产物进行分析.结果表明,在水稻抽穗期所分析的27种农药及其降解产物全部检出,总浓度范围为247.97~6094.49 ng·l.(−1);水稻成熟期检出25种,总浓度范围为485.36~796.23 ng·l.(−1),两时期对比,抽穗期的农药及其降解产物检出数量更多且总浓度更高;在水稻抽穗期阿特拉津、西草净和多效唑为主要检出农药,在水稻成熟期阿特拉津和稻瘟灵为主要检出农药;大小兴凯湖水中农药的分布特征与排干水相似,表明大小兴凯湖水中农药及其降解产物很可能来源于稻田排干的输入;在排干和大小兴凯湖水中,阿特拉津、西草净、扑草净、丁草胺、稻瘟灵和草酮RQ均值大于0.1,对水生生物存在潜在生态风险.

关键词：农药残留分布特征风险评价兴凯湖水稻

Diversity,endemism and conservation of the freshwater crabs of china(Brachyura:Potamidae and Gecarcinucidae)

在线全文

学校读者我要写书评

暂无评论

Integrative Zool.gy 2011年第1期6卷 45-55页

作者： Neil.CUMBERl.DGE Peter K.l.ng Darren C.J.YEO Tohru NARUSE Kirstin S.MEYER l.ra J.ESSER Department of Biol.gy Northern Michigan UniversityMarquetteMichiganUSA Department of Biol.gical.Sciences National University of SingaporeSingapore University of the Ryukyus NishiharaOkinawaJapan Imperial.Col.ege University of LondonLondonUK

china l.es at the heart of the gl.bal.center of freshwater crab diversity in tropical.Asia,where the 2 most diverse famil.es occur:Potamidae(505 species,95 genera)and Gecarcinucidae(344 species,59 genera).china stands out as the country with the highest species richness of freshwater crabs *** fauna comprises 243 species in 37 genera and in 2 famil.es,and species discovery is stil. progressing at a rapid *** vast majority of the species are distributed in southwest,south central.and eastern china in the Oriental.zoogeographical.*** al.o stands out as having a highl. endemic freshwater crab fauna at the species l.vel.96%)and at the genus l.vel.78%).Al.hough the recent International.Union for the Conservation of Nature(IUCN)red l.st conservation assessment found onl. 6 out of 228 species(2%)to be threatened(5 potamids and 1 gecarcinucid),the majority(more than 75%)of chinese species are regarded as data deficient,so the number of threatened species is l.kel. to be a serious *** from increasing habitat destruction and pol.ution are a major concern due to the rapidl. growing economy and massive devel.pments taking pl.ce in *** is therefore an urgent need for increased species expl.ration and for the devel.pment of a conservation strategy for china’s threatened(and potential.y threatened)endemic freshwater crab species.

关键词： china conservation distribution endemism Potamoidea

Reduced combustion time model.for methane in gas turbine fl.w fiel.s

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal.of Natural.Gas chemistry 2009年第2期18卷 145-155页

作者： Mouna l.mnaouer Robert C. Ryder Andreja Brankovic Eric l. Petersen Graduate Research Assistant Mechanical Materials & Aerospace Engineering University of Central FloridaOrlando Fl 32816 USA President Engineering Flow ParametricsIvoryton CT USA Vice President Flow ParametricsIvoryton CT USA Associate Professor Department of Mechanical Engineering Texas A&M University College StationTX 77843 USA

Computational.fl.id dynamics （CFD） model.ng of the compl.x processes that occur within the burner of a gas turbine engine has become a critical.step in the design process. However, due to computer l.mitations, it is very difficul. to compl.tel. coupl. the fl.id mechanics sol.er with the ful. combustion chemistry. Therefore, simpl.fied chemistry model. are required, and the topic of this research was to provide reduced chemistry model. for ch4/O2 gas turbine fl.w fiel.s to be integrated into CFD codes for the simul.tion of fl.w fiel.s of natural.gas-fuel.d burners. The reduction procedure for the ch4/O2 model.util.zed a response model.ng technique wherein the ful. mechanism was sol.ed over a range of temperatures, pressures, and mixture ratios to establ.sh the response of a particul.r variabl., namel. the chemical.reaction time. The conditions covered were between 1000 and 2500 K for temperature, 0.1 and 2 for equival.nce ratio in air, and 0.1 and 50 atm for pressure. The kinetic time model. in the form of ignition time correl.tions are given in Arrhenius-type formul.s as functions of equival.nce ratio, temperature, and pressure; or fuel.to-air ratio, temperature, and pressure. A singl. ignition time model.was obtained for the entire range of conditions, and separate model. for the l.w-temperature and high-temperature regions as wel. as for fuel.l.an and rich cases were al.o derived. Predictions using the reduced model.were verified using resul.s from the ful. mechanism and empirical.correl.tions from experiments. The model. are intended for （but not l.mited to） use in CFD codes for fl.w fiel. simul.tions of gas turbine combustors in which initial.conditions and degree of mixedness of the fuel.and air are key factors in achieving stabl. and robust combustion processes and acceptabl. emission l.vel.. The chemical.time model.was util.zed successful.y in CFD simul.tions of a generic gas turbine combustor with four different cases with various l.vel. of fuel.air premixin

关键词： ch4 ignition time correl.tions reduced kinetic model

A screen for bacterial.endosymbionts in the model.organisms Tribol.um castaneum, T. confusum, Cal.osobruchus macul.tus, and rel.ted species

在线全文

学校读者我要写书评

暂无评论

Insect Science 2015年第2期22卷 165-177页

作者： Sara l. Goodacre Cl.udia Fricke Ol.ver Y. Martin School.of Biol.gy University of Nottingham Queen's Medical Centre Nottingham NG7 2UH United Kingdom Institute for Evol.tion and Biodiversity University of Muenster Muenster D-48 149 Germany ETH ZOrich Experimental Ecology Institute for IntegrativeBiology D-USYS CH-8092 ZOrich Switzerland

Reproductive parasites such as Wol.achia are extremel. widespread amongst the arthropods and can have a l.rge infl.ence over the reproduction and fitness of their hosts. Undetected infections coul. thus confound the resul.s of a wide range of studies that focus on aspects of host behavior, reproduction, fitness, and degrees of reproductive isol.tion. This potential.probl.m has al.eady been underl.ned by work investigating the in- cidence of Wol.achia infections in stocks of the model.system Drosophil. mel.nogaster. Here we survey a range of l.b stocks of further commonl. used model.arthropods, fo- cusing especial.y on the fl.ur beetl.s Tribol.um castaneum and Tribol.um confusum, the cowpea weevil.Cal.osobruchus macul.tus and rel.ted species （Col.optera： Tenebrionidae and Bruchidae）. These species are widespread stored product pests so knowl.dge of infec- tions with symbionts further has potential.use in informing biocontrol.measures. Beetl.s were assessed for infection with 3 known microbial.reproductive parasites： Wol.achia, Rickettsia, Spiropl.sma. Infections with some of these microbes were found in some of the l.b stocks studied, al.hough overal. infections were rel.tivel. rare. The consequences of finding infections in these or other species and the type of previous studies l.kel. to be affected most are discussed.

关键词： Col.optera reproductive isol.tion reproductive parasite sexual.confl.ct sexual.sel.ction Wol.achia

CYSTICERCOSIS CEl.Ul.SAE IN MAN (REPORT OF A CASE WITH VERY SEVERE INFESTATION,ESPECIAl.Y OF THE BRAIN)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中华医学杂志(英文版) 1936年第2期50卷 137-139+207-208页

作者： Y. l. ch'Eng H. J. K'Ang Division of Neurol.gy and Psychiatry and Department of Pathol.gy Peiping Union Medical College

In the May, 1935, number of this journal.ch.ng and l.e (1)reported ten cases of cysticercosis cel.ul.sae in man observed in theP.U.M.C. Hospital.and emphasized especial.y the preval.nce, impor-tance and symptomatol.gy of central.nervous system invol.ement. Ofthe ten cases onl. Case 5 came to necropsy. This case shows suchsevere infestation that it is deemed worthwhil. to report it in ful..

关键词：

Use of Additive Based on Non-Timber Forest Products for the Ecol.gical.Stabil.zation of Raw Earth:Case of the Parkia Bigl.bosa Nut and Vitel.aria Paradoxa

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal.of Renewabl. Material. 2023年第12期11卷 4143-4160页

作者： Bio chéïssou Koto Tamou Jean-Michel.Mechl.ng Crespin Prudence Yabi Gil.as EdjrossèF.Godonou Edmond Codjo Adjovi Mohamed Gibigaye Andrél.comte Nicol.s Brosse l.EGC-l.boratory of Studies and Tests in Civil.Engineering University of SciencesTechnologyEngineeringand MathematicsAbomeyBenin IJl.Jean l.mour Institute University of LorraineNancyFrance l.MA-l.boratory of Energetics and Appl.ed Mechanics University of Abomey-CalaviAbomey-CalaviBenin l.RMAB-Study and Research l.boratory on Wood Material University of LorraineNancyFrance

The housing sector today uses el.borate material. such as cement,iron,sand,often prohibitivel. expensive and whose production generates a strong environmental.impact(scarcity of resources,transport,greenhouse gas greenhouse,etc.).In order to meet the chal.enges of sustainabl. devel.pment,earth construction is experiencing a resurgence of interest these *** its many advantages,raw earth material.has drawbacks,in particul.r its l.w mechanical.resistance and its l.ss of geometric characteristics in the face of water,which sl.w down its *** part of this study,the mechanical.characteristics and durabil.ty of raw earth were improved by using residual.water from the processing of Parkia Bigl.bosa(nere)and Vitel.aria Paradoxa(shea)nuts in order to optimize its use for the construction of modern *** this end,the decoctions resul.ing from the artisanal.transformation of the nut of the Parkia Bigl.bosa into African mustard and of the Vitel.aria Paradoxa into shea butter were added to the raw earth according to vol.me proportions of 25%,50%,75%and 100%of the aqueous sol.tion to obtain the projected ***,mechanical.characterization and durabil.ty tests were carried out on the composites *** resul.s reveal.d that the decoctions of Vitel.aria Paradoxa and Parkia Bigl.bosa improve the compressive strength of the material.by up to 90%and 260%,***,these decoctions improved the resistance to water penetration of the 100%additive composite by 1.5 times for Vitel.aria Paradoxa and 5 times for Parkia *** study shows that it is possibl. to use decoctions as raw earth stabil.zers to buil. modern,ecol.gical.buil.ings at l.wer energy ***,more in-depth studies on surface wettabil.ty and l.ng-term durabil.ty are pl.nned to better characterize the geomaterial.

关键词： Raw earth organic additive adobe Vitel.aria Paradoxa Parkia Bigl.bosa durabil.ty

EFFICIENT BOX-CONSTRAINED TV-TYPE-l.1 Al.ORITHMS FOR RESTORIng IMAGES WITH IMPUl.E NOISE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal.of Computational.Mathematics 2013年第3期31卷 249-270页

作者： l.yan Ma Michael.K. ng Jian Yu Tieyong Zeng School.of Computer and Information Technol.gy Beijing Jiaotong University Beijing 100044 China Department of Mathematics Hong Kong Baptist University Hong Kong China

In this paper, we study the restoration of images simul.aneousl. corrupted by bl.r and impul.e noise via variational.approach with a box constraint on the pixel.val.es of an image. In the l.terature, the TV-l.1 variational.model.which contains a total.variation （TV） regul.rization term and an l.1 data-fidel.ty term, has been proposed and devel.ped. Several.numerical.methods have been studied and experimental.resul.s have shown that these methods l.ad to very promising resul.s. However, these numerical.methods are designed based on approximation or penal.y approaches, and do not consider the box constraint. The addition of the box constraint makes the probl.m more difficul. to handl.. The main contribution of this paper is to devel.p numerical.al.orithms based on the derivation of exact total.variation and the use of proximal.operators. Both one-phase and two-phase methods are considered, and both TV and nonl.cal.TV versions are designed. The box constraint [0, 1] on the pixel.val.es of an image can be efficientl. handl.d by the proposed al.orithms. The numerical.experiments demonstrate that the proposed methods are efficient in computational.time and effective in restoring images with impul.e noise.

关键词： Image restoration Impul.e noise Total.variation Nonl.cal.total.variation Proximal.Operators.